The manufacture of quaternary ammonium compounds is generally carried out by alkylating a tertiary amine to the quaternary stage. The alkylating agent is usually an ester of a strong mineral acid, especially sulfuric or sulfonic acid esters, or an alkyl halide, for reaction with the tertiary amine. Occasionally, other esters are employed. Another known method for alkylating tertiary amines is by reacting alkylene oxides with tertiary amines in the presence of water. A number of other procedures can also be employed to manufacture quaternary ammonium compounds from readily available teriary amines. See, e.g. J. Goerdeler in Houben-Weyl, Methoden der organischer Chemie, 4th Edition, Vol. 11/12, page 592 et seg.
Quaternary ammonium compounds with one or more long, aliphatic radicals, or one long aliphatic radical and one aromatic radical exhibit antimicrobial as well as textile softening and antistatic properties, and they are used extensively for these purposes. Such compounds are obtained either by alkylating tertiary amines having long aliphatic groups and/or aromatic groups, or by alkylating with alkylating agents that contain long aliphatic or aromatic groups. Obviously, the tertiary amine as well as the alkylating agent can each contain long aliphatic and/or aromatic groups.
Disadvantages of these known processes for the manufacture of quaternary ammonium compounds include the fact that usually pressure must be used, and occasionally solvents are also required. In addition, the yield is usually disappointing.